Design and optimization of a 1.3/1.55-μm wavelength selective p-i-n photodiode based on multimode diluted waveguide

This letter demonstrates a new solution to achieve low-cost, highly integrated, and reliable InP-based p-i-n photodiodes for wavelength-division-multiplexing optical networks, absorbing 1.55-μm wavelength and transparent to 1.3 μm. It is based on a multimode diluted waveguide (MDW) combined with an evanescently coupled photodiode. The overall structure is optimized using a genetic algorithm linked to a beam propagation method software. The computed responsivity of the MDW photodiode is 0.86 A/W at 1.55 μm, and the 1.3/1.55-μm optical crosstalk is better than -20 dB (-40-dB electrical). The proposed device is designed for hybridization on silicon platform for low-cost modules, with potential application up to 10 Gb/s.